This is a snippet from http://www.clientcopia.com and is extremely accurate :

• Client won’t supply content

• Client thinks you’ll magically make up content

• Client thinks you can use a competitor’s content

• Client needs the website to be done ASAP while simultaneously not supplying content or getting back to you during the design process

• Client is computer illiterate and expects you to design a wide-target audience website around their inabilities (IE, no scrolling, “CLICK HERE” on links, etc)

• Client thinks they’re a better graphic/UI designer than you are and micromanages you to ultimately creating a shitty website

• Towards the end of development, the client doesn’t understand why you can’t quickly redesign the whole site based on a sudden whim and still meet the deadline

• Client does not understand “dummy text” and “dummy images” and subsequently hates all design concepts – worse when they still won’t supply text or images

• Potential client doesn’t understand why it costs so much, and classicly always has some friend or relative who’d do it for $30 and a pack of beer

• Job postings that require redundant proficiencies, like Dreamweaver, FrontPage and GoLive

• Job postings that require 5 years expirience, a graphic design major, and proficiency in Java, JavaScript, PHP, CGI, .NET and ASP for $9.25/hr